<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS 盒子模型</title>
    <style>
        html * {
            margin: 0;
            padding: 0;
        }
        #box {
            /* width: 200px; */ /* CSS 流式布局 div 自动横向撑满屏幕 */
            height: 100px;
            margin: 15px 20px;
            padding: 10px 5px;
            border: 5px solid #ccc;
            /* box-sizing: border-box; */
        }
    </style>
</head>
<body>
    <p>CSS 盒子模型</p>

    <div id="box">
        计算当前盒子模型的尺寸
    </div>
</body>
</html>